The knife tells surgeons in real time whether tissue is malignant or benign.
Imperial College London

A new surgical knife that leans on both old and new technology could reduce surgery time and the need for follow-up operations by diagnosing cancer midcut.

Developed by Zoltan Takats of Imperial College London, the iKnife is based on a technology that dates back to the 1920s called electrosurgery, where an electrical current rapidly heats tissue to make incisions with minimal blood loss. But it's the vapors from the heated tissue that ultimately come into play.

Instead of sucking away the smoke into extraction systems, Takats decided to connect the knife to a mass spectrometer to analyze the chemicals in the biological sample. (Because different cell types produce metabolites in different concentrations, a biological sample can reveal a lot of detail about the state of the tissue.)

In fact, Takats says there's no reason why the iKnife can't identify many other features beyond tumor malignancy -- think types of bacteria present in a sample, or what a sample actually is. (Horsemeat vs. beef, anyone?)

For this study, which was the first to test the iKnife in an operating room, Takats and colleagues initially tested it on tissue samples collected from 302 surgery patients. It matched its readings of the characteristics of thousands of tissues -- both malignant and benign taken from brains, lungs, breasts, stomachs, colons, livers, and more -- to a database that then reads out in fewer than 3 seconds what type of tissue is being cut.

Then, as they report this week in the journal Science Translational Medicine, the researchers took the knife to the operating theater to perform actual analysis during surgery. In the 91 tests it underwent, the iKnife correctly identified the tissue type every single time.

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"These results provide compelling evidence that the iKnife can be applied in a wide range of cancer surgery procedures," Dr. Takats said in a school news release. "We believe it has the potential to reduce tumor recurrence rates and enable more patients to survive."

Perhaps the biggest drawback, it turns out, is that the surgeons weren't privy to the knife's readings midsurgery -- something the researchers plan to attempt in a clinical trial as they test whether giving surgeons real-time access to the analyses will improve outcomes.

"In cancer surgery, you want to take out as little healthy tissue as possible, but you have to ensure that you remove all of the cancer," added Ara Darzi, professor of surgery and co-author of the study. "There is a real need for technology that can help the surgeon determine which tissue to cut out and which to leave in. This study shows that the iKnife has the potential to do this, and the impact on cancer surgery could be enormous."